Kane Williamson is not a man who telegraphs his emotions too readily. But the look of self-recrimination and fury in the eyes of New Zealand’s captain was unmistakable after the most fleeting moment of arrogance in a supremely humble career managed to turn a calm and collected victory cruise into an agonising scramble across the line.

His side made it… just, by two wickets and with 17 balls to spare, as the bespectacled Mitchell Santner did his best Daniel Vettori impression to ride out a wave of Bangladeshi emotion – on the pitch and in the stands – piercing the covers one last time to end the agonies of the more senior batsmen in the pavilion and seal New Zealand’s status as the first team in this competition to win back-to-back matches.

But the drama that preceded that moment of Kiwi catharsis had to be lived to be believed. The upshot may not have been the encore that the tiger-striped denizens of South London had been rooting for – once again they turned The Oval into a home-from-home to rival the West Indian support here in the 1970s and ’80s – but there was plenty in their team’s performance from which to take heart… not least the heart itself.

Broadly speaking, the rivalry between Bangladesh and New Zealand is characterised by mutual respect. They play one another more often than many sides, drawn together – as they are – by their relative lack of status compared to the big boys of their respective hemispheres. And for the best part of 80 overs of another slow-boiling epic at The Oval, New Zealand appeared to have successfully killed their opponents with kindness.

They had played a canny game in the field after winning the toss and bowling, going hard with the new ball as befits one of the most potent attacks in the game, before easing back through the middle overs and allowing Bangladesh the leeway to make their own mistakes. A steady drip of wickets stymied their initial hopes of another 300-plus total, and left them grateful to reach 244.

And then, in reply, New Zealand produced a similarly quick-slow approach with the bat – a pair of tub-thumping cameos from Martin Guptill and Colin Munro gave way to a poised and dignified 105-stand between Williamson and Ross Taylor, the side’s elder statesmen whose eye for a gap in the covers just about managed to offset their ropey running – Williamson, on 7, ought to have been run out to leave New Zealand wobbling at 60 for 3, only for Mushfiqur Rahim to break the stumps in his eagerness to gather a shy that was set to do the job for him.

It looked at the time like a critical error, and for the next 100 runs, Bangladesh could only rue what might have been. At 160 for 2 after 31 overs, New Zealand needed 85 more in 19 overs, and the jeopardy of the contest appeared to have long since dissipated. But then, back into the attack came the flighted offspin of Mehidy Hasan, and something in Williamson’s icy demeanour melted.

Perhaps he fleetingly allowed his thoughts to stray to that old chestnut, Net Run Rate – given the tightness of the table so far, some unlucky team is bound to find themselves ruing it at some stage. Or perhaps he simply under-estimated the whip of his own elastic wrists. But when Mehidy tossed one into his toes, Williamson succeeded only in a pinpoint flick to deep midwicket, and the ghost of a contest had been stirred.

By the end of the same over, New Zealand were 162 for 4, with Tom Latham gone as well for a duck, stunningly caught by the diving Mohammad Saifuddin at deep midwicket as he got greedy on a long-hop but failed to pick his spot. And suddenly Taylor, so fluent in reaching his 40-ball half-century, was patting back half-volleys and guarding his wicket with his life.

So long as he endured, New Zealand had the game more or less in their control. But on 82, having ground 13 runs from 24 balls since the start of the jitters, Taylor tickled a leg-stump turner from Mosaddek Hossain into the hands of Mushfiqur behind the stumps to deepen his team’s gloom, whereupon Saifuddin took his own cue to rattle the lower-middle order.

Colin de Grandhomme had no answer to a brilliant slower-ball bouncer from Saifuddin, reflexively seeking to ramp it but toe-ending a vertical take-off for the vertically challenged Mushfiqur, and after Mosaddek had lured Jimmy Neesham into a death-or-glory slap to long-off without addition, Saifuddin stormed in once more, swinging a low full toss into Matt Henry’s middle stump with seven runs still needed for victory.

Saifuddin’s hurricane blew out soon afterwards, however. Back-to-back wides, the latter a misdirected yorker, gave way to a slender edge through third man to bring the scores level, whereupon Santner, as cool as the atmosphere was fervent, rifled his drive to finish on a vital 17 not out from 12.

There was disappointment, but little in the way of despondency, from Bangladesh’s players at the end. In previous World Cup campaigns, they would have rued their ill-luck and chastised themselves for crucial missed moments, but they left the field knowing that they had hounded New Zealand every step of the way, and proven beyond any remaining doubt that they are no makeweights in this ten-team draw.

If there was any cause for regret in the post-mortem, it was that their batting had failed to ignite in the manner that it had done in their ODI-record total of 330 in the victory over South Africa. At 82 for 2 after 20 overs, they had laid an impressive platform and withstood the attentions of Trent Boult in particular, whose initial five-over spell was tight but wicketless.

But thereafter, they were stymied by the relentless dot-to-dot discipline of Santner’s left-arm spin, whose ten overs for 41 were dented by a last-ball slap for six, before being pegged back by Matt Henry’s aggressive four-wicket haul. Shakib Al Hasan top-scored with 64 before loosely chopping a long-hop to the keeper, but none of his top eight team-mates managed to emerge beyond the 20s – including Mushfiqur, whose run-out for 19 ended a 50-run stand for the third wicket that briefly had Bangladesh eyeing up 300.

But with a brilliant win and now a very near-miss against two of their apparent superiors, Bangladesh remain every bit as well placed for the semi-finals as any of the teams around them – including the one that has now broken out of the pack to record the first back-to-back wins of the tournament, ESPNCricinfo reports.